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For large interface -> concrete type switches, we can use a jump table on some bits of the type hash instead of a binary search on the type hash. name old time/op new time/op delta SwitchTypePredictable-24 1.99ns ± 2% 1.78ns ± 5% -10.87% (p=0.000 n=10+10) SwitchTypeUnpredictable-24 11.0ns ± 1% 9.1ns ± 2% -17.55% (p=0.000 n=7+9) Change-Id: Ida4768e5d62c3ce1c2701288b72664aaa9e64259 Reviewed-on: https://go-review.googlesource.com/c/go/+/521497 Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Keith Randall <khr@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Keith Randall <khr@golang.org>
121 lines
2.2 KiB
Go
121 lines
2.2 KiB
Go
// asmcheck
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// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// These tests check code generation of switch statements.
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package codegen
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// see issue 33934
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func f(x string) int {
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// amd64:-`cmpstring`
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switch x {
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case "":
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return -1
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case "1", "2", "3":
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return -2
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default:
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return -3
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}
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}
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// use jump tables for 8+ int cases
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func square(x int) int {
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// amd64:`JMP\s\(.*\)\(.*\)$`
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// arm64:`MOVD\s\(R.*\)\(R.*<<3\)`,`JMP\s\(R.*\)$`
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switch x {
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case 1:
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return 1
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case 2:
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return 4
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case 3:
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return 9
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case 4:
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return 16
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case 5:
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return 25
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case 6:
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return 36
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case 7:
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return 49
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case 8:
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return 64
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default:
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return x * x
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}
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}
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// use jump tables for 8+ string lengths
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func length(x string) int {
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// amd64:`JMP\s\(.*\)\(.*\)$`
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// arm64:`MOVD\s\(R.*\)\(R.*<<3\)`,`JMP\s\(R.*\)$`
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switch x {
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case "a":
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return 1
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case "bb":
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return 2
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case "ccc":
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return 3
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case "dddd":
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return 4
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case "eeeee":
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return 5
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case "ffffff":
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return 6
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case "ggggggg":
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return 7
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case "hhhhhhhh":
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return 8
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default:
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return len(x)
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}
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}
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// Use single-byte ordered comparisons for binary searching strings.
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// See issue 53333.
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func mimetype(ext string) string {
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// amd64: `CMPB\s1\(.*\), \$104$`,-`cmpstring`
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// arm64: `MOVB\s1\(R.*\), R.*$`, `CMPW\s\$104, R.*$`, -`cmpstring`
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switch ext {
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// amd64: `CMPL\s\(.*\), \$1836345390$`
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// arm64: `MOVD\s\$1836345390`, `CMPW\sR.*, R.*$`
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case ".htm":
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return "A"
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// amd64: `CMPL\s\(.*\), \$1953457454$`
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// arm64: `MOVD\s\$1953457454`, `CMPW\sR.*, R.*$`
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case ".eot":
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return "B"
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// amd64: `CMPL\s\(.*\), \$1735815982$`
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// arm64: `MOVD\s\$1735815982`, `CMPW\sR.*, R.*$`
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case ".svg":
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return "C"
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// amd64: `CMPL\s\(.*\), \$1718907950$`
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// arm64: `MOVD\s\$1718907950`, `CMPW\sR.*, R.*$`
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case ".ttf":
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return "D"
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default:
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return ""
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}
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}
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// use jump tables for type switches to concrete types.
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func typeSwitch(x any) int {
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// amd64:`JMP\s\(.*\)\(.*\)$`
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// arm64:`MOVD\s\(R.*\)\(R.*<<3\)`,`JMP\s\(R.*\)$`
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switch x.(type) {
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case int:
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return 0
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case int8:
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return 1
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case int16:
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return 2
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case int32:
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return 3
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case int64:
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return 4
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}
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return 7
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}
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